KELLER Pressure 33X Precision Pressure Transmitter
High precision digital pressure transmitter family, ±0.05% FS accuracy in original catalog.
Original manufacturer: KELLER Pressure
Original Documentation
KELLER official model / family specification →
Exact measuring range, output and mechanical connections vary with ordering configuration. Do not treat model family as every orderable part number.
Exact family and Ex safety check
This is standard Series 33X, not the separately certified 33X-Ed flameproof or 33X-Ei intrinsically safe series. Check exact suffix before hazardous-area specification.
Current KELLER product catalog — 33X →
Series 33X — precision pressure versus Ex design
The KELLER 33X precision family lists an accuracy option around ±0.05% FS, so its range and operating temperature can materially affect uncertainty at a given process pressure. Specify pressure reference, digital configuration and traceable verification before using it as an instrumentation reference. The standard 33X is not the 33X-Ed flameproof Ex db family: shared digital pressure design does not make its enclosure or cable entry explosion-protected.
33X: distinguish 0.05% accuracy from 0.1% total error band
| Engineering item | Manufacturer data / qualifier |
|---|---|
| Range selections | 0–0.3 through 0–1,000 bar |
| Reference accuracy | ±0.05% FS standard accuracy at reference conditions |
| Total error band (TEB) | ±0.1% FS total error band at −10…+80°C; catalogue cites optional 0.01% FS under qualified calibration |
| Signal interface | RS485 digital and orderable scalable analogue 4–20 mA / 0–10 V |
| Integration details | The digitised correction model enables much finer pressure accuracy than 21Y or 23SY, but no universal 0.01% accuracy is guaranteed by choosing the 33X series alone. KELLER says 0.01% can be achieved after optional added measurements/selections and an accredited laboratory calibration. Standard 33X is not interchangeable with the flameproof 33X-Ed enclosure. Series temperature −40…+125°C. |
Procurement and error-budget check
Catalogue figures describe the manufacturer’s model family rather than every configured order code. Select correct wetted materials, port/seal, absolute versus gauge reference, thermal error budget and wiring schematic. FS accuracy is not accuracy as a percentage of the actual reading. Manufacturer range temperature does not mean published TEB applies at every temperature. Any Ex/ATEX/IECEx approval must be demonstrated for the exact ordered variant.
Original manufacturer specification: KELLER 33X Precision Pressure Transmitter.